Replace instances of one Block with another
Trim Shapes
Cataloged Blocks may be associated with one of five shapes, that allow a Block Insert to trim AutoCAD simple entities like: LINE, POLYLINE, LWPOLYLINE, CIRCLE, ARC, ELLIPSE. Don't use that Break command to break lines around your Blocks - define Trim Shape for that block and use Shape Trim Action tool to trim around any number of selected blocks at once!
Smart Dialog Boxes that adjust "on the fly" minimizing waste of your precious screen space
Insert Options
associate a block with unlimited combinations of insert parameters (Scale, Layer, Color, Linetype, Attributes, Trim Shape). You can select that combination when block is inserted instantaneously transforming it to desired form and properties
Modify:

Support of Departmental Drawing Standards by associating cataloged Blocks with Insert Properties (Insertion Layer, Color, Linetype)
Standards Manager - Use this module to assign Insert Properties to Libraries instead of going through very tedious task of configuring Insert Properties for each block separately. Selected insert properties will be applied to all blocks in the library.
You can preset a standard for each client and switch to that standard on the fly by one click of a mouse from BC main dialog
User Administration
assign read, write or administration rights to BC users accessing same database through network
BC Reporter
print out contents of your libraries
Instantaneous Access:

Screen Pick – start using a block by "Picking" it from the drawing
Select from History File
BC maintains references of used blocks in History File for fast retrieval. History File could be saved under logical name and later retrieved from another drawing
Search For Block by typing its name, description or search pattern
Select Block from Slide Library
Extensive Resources:

BC Exchange - powerful means for BC users to exchange block libraries for free. You can submit your libraries to be published on this page or just download from the list
BC Tips - concise guide on how to accomplish different tasks with Block Controller
BC Movie Theater - collection of interactive tutorials on basic and advanced topics